KEY TAKEAWAYS
- A 25-person company on a legacy PBX or carrier-bundled system pays $1,800-$2,400/month in 2026. Switching to VoIP cuts that to $375-$875/month depending on provider and add-ons.
- The “starting price” on vendor pricing pages is not what you pay. AI add-ons, SMS bundles, and number porting fees push the true per-seat cost 30-80% above the advertised rate.
- RingCentral, Zoom Phone, and Nextiva all run active affiliate programs. Most review sites ranking them receive referral commissions. This article uses zero affiliate links.
- Ooma and Zoom Phone are the only two providers in this comparison that offer no mandatory annual contract at small seat counts.
A 25-person company still running on a legacy PBX or carrier-bundled phone system is spending an average of $1,800-$2,400/month in 2026. Switching to the right VoIP provider cuts that bill to $375-$875/month on day one, but only if you pick the right plan structure for your call volume.
This article covers six providers: RingCentral, Zoom Phone, Nextiva, Ooma Office, Vonage, and Dialpad. I show the all-in cost at month 12, not the starting price on vendor pricing pages. The two traps I expose: AI add-on fees that appear after you sign, and annual contract requirements that trigger re-tier penalties when headcount changes.
I’ve run cost models for teams ranging from 6 to 200 seats, and the number that always shocks people is not the base rate. It’s what the invoice looks like at month 12. Jump to the comparison table if you need a number today. Read Section 3 before you sign anything.
All 6 VoIP Providers at a Glance: Starting Price, True Cost, and Best Fit
Before I build a 12-month model for any client, I always start here. This table tells you who to eliminate before you spend an hour on a demo.
| # | Provider | Starting Price | True Cost / 25 Seats | Contract? | Best For | |
|---|---|---|---|---|---|---|
| 1 |
 |
$20/user/mo | ~$750-$875/mo | Annual for $20 rate | CRM-heavy sales teams 50+ | Visit → |
| 2 |
 |
$10/user/mo (metered) | ~$375-$475/mo | No | Remote teams already on Zoom | Visit → |
| 3 |
 |
$17.95/user/mo | ~$449-$649/mo | Annual | Teams wanting one bundled bill | Visit → |
| 4 |
 |
$19.95/user/mo | ~$499/mo | No | Under-15-seat teams, no contract | Visit → |
| 5 |
 |
$13.99/user/mo | ~$525-$580/mo | Annual | Dev teams needing API access | Visit → |
| 6 |
 |
$15/user/mo | ~$375-$440/mo | Annual | AI-native teams, Google Workspace | Visit → |
True Cost at 25 Seats includes base seat fee + AI add-on (where not bundled) + SMS bundle + standard onboarding. Number porting fees excluded (see Section 3). All prices verified April 2026 at vendor pricing pages. RingCentral’s $20/user rate requires annual contract; month-to-month is $30/user.
What You Actually Pay at Month 12: The Line-Item Reality
This is the model I build in a spreadsheet before I recommend any platform. The starting price is a marketing number. The month-12 effective rate is the operational number.
RingCentral – True Cost at 25 Seats
Base rate: $20/user/month on annual contract (confirmed at ringcentral.com, April 2026). At 25 seats, that’s $500/month. Add the RingCentral AI add-on at $9.99/user/month ($249.75) and SMS bundle at $4.99/user/month ($124.75).
Month-12 total: approximately $875/month for 25 seats, or $34.98/user effective. If you opt out of AI and SMS, the rate drops to $20/user, but I have never seen a sales team at 25+ seats opt out of SMS in 2026. It is table stakes.
Zoom Phone – True Cost at 25 Seats
Zoom offers two US/Canada plans: metered at $10/user/month and unlimited at $15/user/month (confirmed at zoom.us, April 2026). Most businesses need unlimited. At 25 seats on unlimited: $375/month base.
Add Zoom AI Companion at $5/user/month ($125) and SMS add-on at $3.99/user ($99.75). Month-12 total: approximately $475/month for 25 seats with AI, or $18.99/user effective on unlimited. Critical note: Zoom Phone delivers full value only if your team already pays for Zoom Meetings ($18.33-$22.49/user/month). For a team switching cold, the bundled cost narrows the gap with Nextiva fast.
Nextiva – True Cost at 25 Seats
Nextiva’s Essential plan starts at $17.95/user/month at 25+ seats (confirmed at nextiva.com, April 2026). At 25 seats: $448.75/month. AI features and core messaging are bundled at this tier with no separate add-on line item.
Month-12 total: approximately $449/month for 25 seats, or $17.95/user effective. Nextiva is the closest thing to a “no surprises” invoice in this category. For a CFO who hates line-item creep, that has real operational value even compared to Zoom Phone’s lower base rate.
Dialpad – True Cost at 25 Seats
Standard plan at $15/user/month on annual (confirmed at dialpad.com, April 2026). At 25 seats: $375/month. AI call transcription, coaching, and automated summaries are included in every plan. No separate AI add-on.
Month-12 total: approximately $375-$440/month for 25 seats depending on SMS needs. At 25 seats, choosing Dialpad over RingCentral for AI saves approximately $249.75/month, or $2,997/year. That is the single largest cost difference in this comparison.
Three Costs Nobody Warns You About Before You Sign
I’ve had clients come back to me 90 days after signing a VoIP contract with three line items on their invoice they didn’t see coming. All three are in this section.
Number Porting Fees: The $400 Surprise
Ask your sales rep: "What is your per-number porting fee, and what is the average porting window for my area code?" If they hesitate, get it in writing.
Porting fees range from $0 (Ooma) to $39.99/number (Vonage, confirmed April 2026). A company with 10 direct-dial numbers moving to Vonage faces a $399.90 one-time charge nobody puts in the proposal.
In our practice, we see 7-day average porting windows for US local numbers. During the porting window, you are paying both the old carrier and the new VoIP provider. Budget for 1-2 weeks of overlap billing.
Annual Contract Lock-In and the Re-Tier Penalty
RingCentral’s advertised $20/user rate requires annual commitment. Month-to-month is $30/user (confirmed at ringcentral.com, April 2026). A 6-person startup signs annual at $20/user = $120/month. They grow to 15 seats mid-contract. New seats are billed at month-to-month rate ($30/user) until renewal.
If 6 months remain on the contract when headcount doubles: extra cost = $90/month for 9 new seats x 6 months = $540 that nobody budgeted. Every fast-growth startup I advise takes the no-contract option for the first year, even if it costs 20-30% more per seat. The flexibility is worth it at under 20 employees.
AI Add-On Creep: The Feature That Appears After Your Demo
In 2026, every major VoIP provider has added an AI tier. Almost none bundle it in the base plan. RingCentral AI: $9.99/user/month add-on (confirmed April 2026). Zoom AI Companion for Phone: $5/user/month. These are the features your sales rep demonstrated in the demo.
Dialpad is the exception. AI call transcription and coaching are included in the base plan at every tier (confirmed at dialpad.com, April 2026). At 25 seats, choosing Dialpad over RingCentral for AI saves $249.75/month, or $2,997/year. Always ask: “Is AI included in the plan you showed me, or is it an add-on?” Then get the answer in writing.
Which VoIP Provider Fits Your Team Size
The most common mistake I see is a 12-person startup evaluating enterprise-tier features they will not use for two years, while ignoring the contract terms that will cost them real money in six months.
Under 10 Seats
Recommended: Ooma Office at $19.95/user/month with no contract and $0 porting fees. Do not sign RingCentral or Vonage annual contracts at this size. If you add 2 seats in month 4, you are mid-contract without negotiating power.
Dialpad is a strong alternative if AI call transcription matters to your small team. At $15/user/month with AI included, it is the most feature-dense option at this size band.
10-30 Seats
Recommended: Zoom Phone (if already on Zoom Meetings) or Nextiva (if you want a single bundled bill). The true cost gap between Zoom Phone ($18.99/effective with add-ons) and Nextiva ($17.95/effective bundled) narrows significantly at 25 seats when you factor in Zoom Meetings subscription cost.
Annual contract is acceptable at this size if headcount is stable. Do not sign annual if you are hiring aggressively.
30-100 Seats
Recommended: RingCentral (if CRM-heavy) or Nextiva (if invoice simplicity matters). RingCentral’s Salesforce and HubSpot integrations are natively deeper than Nextiva’s at this seat count. At 50 seats, the $34.98/user effective on RingCentral vs $17.95 on Nextiva = $17.03/seat difference x 50 = $851.50/month. That delta needs to be justified by CRM integration value.
100+ Seats
At 100+ seats, none of these self-serve plans apply. You are in enterprise territory with custom negotiated pricing. At this size, the decision variables shift: SLA uptime guarantees (99.999% vs 99.9% = 8.7 hours/year downtime difference), dedicated customer success, and integration support SLAs matter more than per-seat rate.
Provider-by-Provider: What the Review Sites Don’t Tell You
I’m going to give you the version of each assessment you won’t find on vendor websites or affiliate review sites: where they genuinely outperform peers and where I’ve seen them fail.
RingCentral
- Deepest native CRM integrations (Salesforce, HubSpot, Zendesk)
- Most mature analytics dashboard in the category
- 99.999% uptime SLA
- Highest true cost after AI and SMS add-ons ($34.98/user effective)
- Annual contract required for advertised price
- AI is an add-on, not a bundle ($9.99/user/month extra)
RingCentral is the right answer for a 40-person B2B sales team where every rep is on Salesforce all day. It is the wrong answer for a 10-person remote startup that mostly uses Slack.
Zoom Phone
- Lowest per-seat base cost ($10-$15/user/month)
- No annual contract required
- Seamlessly embedded in Zoom client your team already uses
- Full value only if already paying for Zoom Meetings ($18-$23/user extra)
- AI Companion is a paid add-on ($5/user/month)
- No desk phone hardware bundle included
Zoom Phone makes immediate financial sense exactly once: when you already have a Zoom Meetings subscription. For everyone else, the "cheapest" base price is a misdirect. Teams with heavy international call volume should run a separate international cost model.
Nextiva
- Most predictable invoice: no AI add-on stacking at 25+ seats
- Strong support reputation across team sizes
- Unified voice, video, and messaging in one platform
- Higher base rate than Zoom and Dialpad ($17.95/user)
- Less mature third-party CRM integration than RingCentral
- No free trial in 2026
I recommend Nextiva to CFOs who have been burned by surprise invoices. The bundled price is not the cheapest, but it is the most predictable. In a 30-person company, “no surprises” has real operational value.
Ooma Office
Best for: 5-15 person professional services firms that need reliable calling with no contract risk. $19.95/user/month (Essentials) or $24.95/user/month (Pro), $0 porting fee, no annual commitment. Limitation: No native CRM integrations at RingCentral depth. Not appropriate for contact center use cases. Analytics are basic.
Vonage Business
Strongest fit: Teams with a developer on staff who will use the Vonage API platform for custom call routing. Mobile plan starts at $13.99/user/month (annual).
Limitation: Highest porting fee at $39.99/number. Video calling excluded from base plan (separate $9.99/month add-on).
Dialpad
Ideal for: AI-native teams and Google Workspace shops. $15/user/month standard with AI transcription, coaching, and summaries included in every tier.
Limitation: Less mature contact center features at enterprise scale. Some users report call quality degradation on poor Wi-Fi connections
What Is the True All-In Cost of VoIP for a 25-Person US Business in 2026?
For a 25-person US business in 2026, the true all-in monthly VoIP cost ranges from approximately $375/month (Zoom Phone metered or Dialpad with AI included) to $875/month (RingCentral with AI and SMS add-ons). The spread is driven almost entirely by AI feature add-ons and SMS bundling, not the base seat rate you see on pricing pages.
The math: $15/user effective (Dialpad or Zoom metered) x 25 = $375/month at the low end. $34.98/user effective (RingCentral full stack) x 25 = $874.50/month at the high end. The $499.50/month gap equals $5,994/year.
The one variable that moves these numbers significantly: number porting fees (one-time, $0 to $400 depending on provider) and the overlap billing window during porting (typically 1-2 weeks of double billing). The legacy system you’re replacing likely costs $1,800-$2,400/month, so the switch pays for itself in month one regardless of which provider you choose.
Five Questions to Ask Every VoIP Provider Before You Sign Anything
I give every client this list before their first demo. The answers tell you more about a provider than their feature matrix ever will.
1. “Is the price you’re showing me the annual-contract rate, and what is the month-to-month rate?” RingCentral: $10/user difference between annual ($20) and month-to-month ($30). Get the month-to-month rate in writing before signing.
2. “What is your per-number porting fee, and what is the average porting window for my area code?” Budget for $0-$39.99/number depending on provider. Confirm porting timeline in writing.
3. “Is AI included in this plan, or is it a separate line item?” If it was in the demo, it should be in the contract. At 25 seats, an undisclosed $9.99/user AI add-on = $249.75/month you did not budget.
4. “What happens to my per-seat rate if I add employees mid-contract?” Some providers bill new seats at the month-to-month rate until annual renewal. Get the “mid-contract add-seat rate” in writing.
5. “What is the contract exit clause and early termination fee?” Most annual contracts include an ETF equal to remaining months x monthly fee. For a 25-seat team at $34.98/effective rate, an ETF on 6 remaining months = $5,247.
Zoom Phone's metered plan starts at $10/user/month, making it the lowest advertised rate. The unlimited US/Canada plan is $15/user/month. If you need a no-contract option with zero porting fees, Ooma Office at $19.95/user/month is the better value for teams under 15 seats. At 25 seats, RingCentral's true cost is approximately $875/month versus Zoom Phone's $475/month. That $4,800/year gap is worth it if your team uses Salesforce or HubSpot daily. If your team does not rely heavily on a CRM, Zoom Phone or Dialpad delivers comparable calling quality at materially lower cost. Yes, number porting is standard across all six providers. Fees range from $0 (Ooma) to $39.99/number (Vonage). The porting window averages 5-10 business days for US local numbers. Budget for 1-2 weeks of overlap billing between your old carrier and new provider. Most modern VoIP providers are softphone-first: your team uses a desktop or mobile app with no hardware required. If you want desk phones, expect $80-$250/handset for Poly, Yealink, or Cisco IP phones. For a 25-person team going softphone-only, hardware cost is $0. The standard contract is 12 months, which unlocks the advertised per-seat rate. Month-to-month exists at Ooma and Zoom Phone, but rates are typically 30-50% higher. RingCentral month-to-month is $30/user versus $20/user on annual: a 50% premium for flexibility. The true month-12 cost ranges from $375/month (Dialpad or Zoom metered) to $875/month (RingCentral full stack) for 25 seats. Add one-time porting cost of $0-$400. The legacy system you're replacing costs $1,800-$2,400/month, so the switch pays for itself in month one.Frequently Asked Questions: Best VoIP Providers 2026
What is the cheapest VoIP service for a small business in 2026?
Is RingCentral worth the higher price compared to Zoom Phone?
Can I keep my existing phone numbers when switching VoIP providers?
Do I need new hardware to switch to a VoIP phone system?
What is the average contract length for business VoIP providers?
What is the true all-in cost of switching to VoIP for a 25-person company?
The Bottom Line: Which VoIP Provider Should You Actually Sign With?
Across six providers at 25 seats, the true cost gap is $375-$875/month. That $500/month spread is driven by AI add-ons and SMS bundles, not base rates. Porting fees add $0-$400 one-time. Contract lock-in creates re-tier risk for fast-growing teams under 20 seats.
Dialpad saves $2,997/year over RingCentral for AI features alone, because it bundles what RingCentral charges extra for. Nextiva delivers the most predictable invoice. Ooma carries the lowest switching risk for small teams. Zoom Phone is the cheapest base rate but only makes sense if you’re already paying for Zoom Meetings.
Start with the comparison table at the top. Eliminate the providers that don’t fit your team size. Then run the five pre-signing questions from Section 5 on your top two candidates. That process cuts a 6-week vendor evaluation to 10 days.
